Effect of Gate Geometry on Reliability Characteristics of Low-k Dielectrics

• Main Authors: Chi Jia Huang, 黃麒嘉
• Other Authors: 鄭義榮
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/14756231475144693166

碩士 === 國立暨南國際大學 === 電機工程學系 === 103 === This study consists of two parts. The first part study the effects of the metal gate geometry on the reliability characteristics of low-k dielectric films using metal-insulator-semiconductor (MIS) structures have been investigated. Weibull slopes (β), area scaling factor, electric-field acceleration factor, and dielectric breakdown projection model have been checked in order to further understanding of the breakdown mechanism of low-k dielectrics films. Compared to SiO2 and dense low-k dielectric films, the porous low-k dielectric films have a lower β value and electric-field acceleration factor. Additionally, there are a larger derivation in dielectric breakdown projection model (E and models) and single Weilbull plot of the breakdown time distributions from various areas merge for the porous low-k dielectric films. Furthermore, the metal gate geometry also influence the dielectric breakdown time. The porous low-k dielectric films in the irregular-shaped metal gate MIS structures have the largest dielectric breakdown time although the sustained electric field within the film is higher. A mechanism was provided in this study. The second part study the effects of different cleaning solutions and various immersion times on the physical, electrical, and reliability characteristics of dense and porous low-k dielectric films were investigated in this study. After immersing into a wet cleaning solution, both low-k dielectric films are needed to remove the physically-adsorbed water by a post-baking process in order to ensure a better performance. The experimental results indicated that irrespective of acid HF and basic NH4OH solutions, they would cause negative impacts on the low-k films, even performing a post-baking process due to the existence of chemically-bonded moisture. The formation of chemically-adsorbed moisture was serious for the porous low-k dielectric films in the NH4OH solution. In addition to the adsorbed moisture, the HF solution caused the low-k dielectric's structure and porosity to be modified and its impact increased with the immersion time. Except the positive benefit in reducing the dielectric constant, these changes caused the degradation in electrical and reliability performance for low-k dielectric films.